compare dots in two binary images

I have two binary images(Image1 & Image2). Both images have dots. The images belong to the same scene but taken at different times

I would like to identify the same dots in image 1 and image 2 Missing dots in image 2 New dots in image 2

I am also attaching the images here.

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can someone help. Thanks

Answer 1

[Image Analyst]

Only 1 image is attached. Why do you want to do this? Whatever you want to do, I think there might be a better way than matching up hundreds of dots. I see a lot of ambiguity. Since they look like single pixels there is a high probability they may either be there or not be there depending on their location over a pixel and their brightness. For example, what if the dot in your scene lands in the corner of 4 pixels on your sensor and now each detects only 1/4 the light from it as when it was perfectly situated over a pixel sensor? It might not be detected at all. If you really do want to match up dots, you can check out the Groth algorithm which is used in Astronomy to match up stars, and has even been used to identify individual whale sharks by their spots. But again, I don't think this is the right approach for whatever you want to do.

[Yuvashree Mani Urmila]

I want to do this because i want to know the new signals and already existing signals. Already existing signals will be in the same position in both images, I was thinking of obtaining the pixel positions of the signals. What will be the best way to analyse this signals in the form of dots.

[Image Analyst]

What is the signal? Is it one single dot? Or is it the whole pattern of dots? What physical phenomenon gave rise to the dots?

[Yuvashree Mani Urmila]

one single dot for one signal(one single pixel). they are biological signals from cells

[Image Analyst]

You might try imregister to try to align them. Then compare them.